1. Field of the Invention
Methods and apparatuses consistent with the present invention relate to booting a host, and more particularly, to booting a host in which a downloadable conditional access system (DCAS) is embodied.
2. Description of the Related Art
A broadcasting service provider limits the number of channels a broadcasting service subscriber can watch according to a service subscription fee the broadcasting service subscriber pays. In other words, a broadcasting service provider differentiates a broadcasting service for all broadcasting service subscribers and a broadcasting service only for broadcasting service subscribers paying an additional broadcasting service subscription fee. In the former case, the broadcasting service provider transmits a part of broadcasting data without encryption such that all broadcasting service subscribers can receive a broadcasting service regarding the broadcasting data. In the latter case, the broadcasting service provider transmits the other part of broadcasting data with encryption such that only the broadcasting service subscribers who paid the additional broadcasting service subscription fee can receive a broadcasting service regarding the encrypted broadcasting data.
A conditional access system (CAS) is the most typical system for controlling channels a broadcasting service subscriber can watch. To embody the CAS, a broadcasting service provider encrypts a part of broadcasting data and transmits the encrypted broadcasting data. In this case, an entitlement management message (EMM) and an entitlement control message (ECM) are transmitted along with the encrypted broadcasting data.
A broadcasting reception device of a broadcasting service subscriber who pays an additional broadcasting service subscription fee includes a security module capable of decrypting the encrypted broadcasting data. The security module receives the EMM data and verifies whether the broadcasting reception device is authorized to receive the broadcasting data. For example, the security module can verify whether the broadcasting reception device is used by an authorized broadcasting service subscriber or not by comparing a serial number of the broadcasting reception device and the EMM data. Once the broadcasting reception device is verified as an authorized device, the security module verifies whether the broadcasting reception device is authorized to receive the encrypted broadcasting data or not by using the ECM data. To this end, the security module generates a decryption key by using a verification key, which is obtained from the EMM data, and the ECM data, only if the broadcasting reception device is authorized to receive the encrypted broadcasting data. The broadcasting reception device decrypts the encrypted broadcasting data so that the broadcasting service subscriber can receive a broadcasting service regarding to the encrypted broadcasting data.
Meanwhile, it is prescribed in an open cable application platform (OCAP), which defines the standards of cable broadcasting, that it is required to use a cable card as a security device. However, such cable card is expensive and difficult to be upgraded. To resolve the problems of such cable card, a downloadable CAS (DCAS) is currently under development. In the DCAS, the tasks for a conventional cable card are distributed to a hardware-based security module and a software-based client. The hardware-based security module is included in a broadcasting reception device, whereas the software-based client can be downloaded from a broadcasting service provider.
In the DCAS, functions provided by a broadcasting reception device vary according to a condition of the broadcasting reception device. Thus, it is effective to switch a booting method or a booting sequence according to a condition of the broadcasting reception device. However, an initial boot-up of a broadcasting reception device has been performed inefficiently in a conventional DCAS without considering a condition of the broadcasting reception device.